There are various machines that operate to receive information from, or impart information to, magnetic tape. Two such commonly used machines are video player/recorder units and audio player/recorder units. In the video units, the magnetic tape is pulled outwardly from a cassette tape cartridge and brought into engagement with a shallow cylindrical surface of a rotating element on which the player/recorder head is carried. In the audio unit, the magnetic tape generally extends across a forward portion of the tape cassette, with the tape being exposed at this forward portion. The tape passes by a stationary player/recorder head, and is also engaged by a capstan and pinch roller of the machine to cause the tape to move along its length.
Various cleaning devices have been proposed to clean the operating surfaces of such player/recorder units. With the video unit, it has been a common practice to provide a cleaning ribbon that is engaged by guide elements in the video player/recorder unit to carry the cleaning ribbon into engagement with the rotating element carrying the player/recorder head and possibly into engagement with other components of the video player/recorder unit.
Another type of cleaning mechanism that is used more commonly with audio player/recorder units comprises a cassette housing that carries a cleaning member that in turn is adapted to carry a cleaning element, such as a pad. This cleaning member is arranged to move on a cleaning path, which in many cleaning devices is a back-and-forth path where it wipes against the player/recorder head of the audio unit. Quite commonly, the cleaning member is driven on its back-and-forth path through a suitable drive transmission from one of the drive spindles in the audio player/recorder unit.
To obtain the proper cleaning action, it is desirable to have adequate frictional engagement between the cleaning pad and the surface of the player/recorder head of the audio unit. However, if the force of the frictional engagement is excessive, then the resistance imparted back through the drive transmission to the drive sprocket may trigger the automatic shutoff mechanism in the machine.
Another concern is that the operating surface of the player/recorder head is quite often not a flat surface, but a moderately curved surface. Also, in some instances, the operating surface of the head may be a compound curved surface, having two or more curved side portions, with a moderate recess between the curves, or with ridges and small crevices. This may have a tendency to create a resisting force against the cleaning pad greater than that that would normally be encountered simply from frictional engagement.
Another consideration is that the location of the player/recorder head will vary from machine to machine. Thus, the cleaning element (i.e., usually the cleaning pad) must be mounted in such a way that it can be positioned at different forward-to-rear locations and still be in proper cleaning engagement with the player/recorder head.
One common means of mounting the cleaning element is to place it on an arm that is pivotally mounted for back-and-forth motion about a pivot location in the center portion of the cassette housing. To accommodate different forward-to-rear locations of the cleaning element, there is sometimes provided a spring arm, which in one form can be a U-shaped spring section, such as shown in U.S. Pat. No. 4,225,893 (Loiselle). This patent shows another method of accommodating this difference in forward-to-rear location of the cleaning element. The lever arm itself is secured with a pin-and-slot connection so that it can shift forwardly or rearwardly as the pivot arm swings back and forth about the pivot location to accomplish the cleaning motion on the surface of the head. A spring biases the arm in a forward direction.
With regard to the problem of the cleaning element being caught or snagged on the surface of the player/recorder head (e.g., possibly being engaged by a side surface portion of the head so as to create a relatively large resistance to the back-and-forth movement of the cleaning element), one approach to this problem, as shown in U.S. Pat. No. 4,454,551 (Clausen et al.), is to provide the arm that carries the cleaning pad with a spring having a somewhat "Z" configuration, where the spring has two oppositely positioned U-shaped spring sections.
In yet other instances, the cleaning element is mounted to a carder that, instead of a pivot motion, has a linear side-to-side motion, with the carrier or carriage for the cleaning pad having a laterally extending member mounted between pins. An example of this is shown in U.S. Pat. No. 4,442,468 (d'Alayer de Costemore d'Arc).
Other pans of both video and audio player/recorder units also need cleaning besides the play/record heads. Foreign particles, such as oxidation from magnetic tapes and dust, accumulate on drive capstans and pinch rollers as well as heads. Such pollution may cause the player and/or recorder units to lose proper drive control of the tape. Problems of tape speed, jamming, and other erratic behavior can result. Attempts have thus been made to clean elements, such as capstans and pinch rollers, in addition to the heads. An example of a capstan and pinch roller cleaner is shown in U.S. Pat. No. 4,454,550 (Clausen et al.). The cleaning cassette disclosed therein includes a cleaning arm for the head, which is driven by drive spindles of the player/recorder unit, and a cleaning cartridge for the capstan and pinch roller.
In addition to video and audio player/recorder units, there are also tape drives that move a magnetic tape relative to a read/write head so that data can be taken from the tape or transmitted to the tape. Common drives are provided a read/write head that is positioned at a front location relative to the tape cassette, and the operating surface of this head has a pair of vertically oriented ridges that protrade outwardly from the operating surface a short distance. With regard to cleaning such a read/write head, for example by a back-and-forth motion of a pad, these ridges aggravate the problem of the cleaning pad encountering an excessive resisting force by the pad coming into engagement with the side surfaces of these ridges.
In this tape drive machine, there is a drivewheel (i.e., a capstan) that engages a drive element in the tape cassette to cause movement of the tape. The operation of the machine is such that the motion imparted to the tape is a somewhat erratic back-and-forth motion.
In U.S. Pat. No. 4,816,952 (Clausen) there is described a cassette cleaner to clean the read/write head of the tape drive machine. There is a cassette housing having a carriage mounted for lateral back-and-forth movement in the housing. The carriage has a slot-and-pin mounting at a left forward location, and a cleaning pad at a right forward location, with a gear and cam transmission to cause the lateral back-and-forth motion of the carriage. Power to the gear and cam transmission is supplied by a drivewheel 78 that engages a roller or drive capstan 16, which is a component of the tape drive machine.
While the cassette cleaner described in U.S. Pat. No. 4,816,952 cleans the read/write head, there is still the problem of cleaning the capstan or drive roller of the tape drive machine. Also, as the drive units seem to have faster and faster drives, additional problems of cleaning-cassette noise and excessive speed of the head-cleaning pad emerge. The gear-driven system disclosed causes disconcerting noises in high-speed drives. Also, if the speed of the head-cleaning pad is too high, it will not effectively clean the irregular surface of the head.
The main impediment to cleaning the capstan of a tape drive unit, such as that discussed above, is the arrangement of the standard drive such that the sole driving element of the unit is the capstan. Thus, the cleaning cassette drive mechanism to clean the head must engage the capstan and no adequate access to the capstan remains for cleaning of the capstan itself, which, as discussed above, also becomes polluted.
One solution to the capstan-cleaning problem in tape drive units was made by the present inventor and disclosed in U.S. Pat. No. 4,894,743. The disclosed cleaning cassette utilizes separate replaceable cleaner/drive members, one for providing driving engagement with the capstan to move a head cleaner pad and a second providing a capstan-cleaning pad and no driving engagement.
However, the system of U.S. Pat. No. 4,894,743 requires separate members that may be misplaced or not used. The system also relies on a gear-driven transmission that may be noisy, especially with high-speed drives. The system also may not provide enough speed reduction for high-speed drives, such that the head may not be effectively cleaned.
Therefore, owing to the drawbacks of the above-described cleaning devices, particularly in meeting the requirements of tape drive units where a capstan provides the sole driving force, the present invention was developed. The present invention effectively cleans both the head and capstan without separate parts or members and reduces head cleaner speed and drive transmission noise.